Fabric effect for fibrous glass fabrics

ABSTRACT

FIBROUS GLASS FABRIC HAVING PESUDO-EMBOSSED EFFECTS, COMPRISING WARP AND WEFT YARNS LYING IN LATERALLY AND VERTICALLY RANDOMLY SHIFTED, STRESS-RELIVED AND COMPACTED EQUILIBRIUM CONFIGURATIONS OF THE ORIGINAL WAVE PATTERN WHEREIN THE YARNS WERE ORIGINALLY IN A STRESSED CONDITION DUE TO THEIR DISPLACEMENT FROM AN ESSENTIALLY STRAIGHT CONFIGURATION INTO SINUSOIDAL PATHS IN THE ORGINAL WAVE PATTERN.

.Mauth 13, 1973 R, F, cARosELLl ET AL 3,720,571

I FABRIC EFFECT FOR FIBROUS GLASS FABRICS Original Filed sept. a, 196e 4Sheets-Sheet 2 Mach 1.3, 1973 R. F. cARosELLx ET AL 3,720,571

FABRIC EFFECT FOR FIBROUS GLASS FABRICS Original Filed Sept. 8, 1966 4Sheets-Sheet 3 f/wf/vrowsk REMUS @m55/ U JAM/55d D/LLOA/ DAV/D E. Ln/wMarch 13, 1973 R, F,CAROSEL L| ET AL 3,720,571

- FABRIC EFFECT FOR FIBROUS GLASS FABRICS- Original Filed Sept. 8, 19664 Sheets-Sheet 4 BYMY ATTORNEYS United States Patent 3,720,571 FABRICEFFECT FOR FIBROUS GLASS FABRICS Remus F. Caroselli, Cumberland, .lamesJ. Dillon, Providence, and David E. Leary, Cumberland, RJ., assignors toOwens-Corning Fiberglas Corporation Griginal application Sept. 8, 1966,Ser. No. 578,430, now Patent No. 3,571,871. Divided and this applicationMar. 19, 1971, Ser. No. 126,093

Int. Cl. D03d 3/00 U.S. Cl. 161-73 4 Claims ABSTRACT F THE DISCLOSUREFibrous glass fabric having pseudo-embossed effects, comprising warp andweft yarns lying in laterally and vertically randomly shifted,stress-relieved and compacted equilibrium configurations of the originalweave pattern wherein the yarns were originally in a stressed conditiondue to their displacement from an essentially straight configurationinto sinusoidal paths in the original weave pattern.

This is a divisional application of Ser. No. 578,430, filed Sept. 8,1966, now U.S. Pat. No. 3,571,871.

The present invention relates to methods for imparting decorative weaveeffects and designs to fibrous glass fabrics in a post-weaving processand particularly to methods comprising the transformation of stressesexisting in a given weave design to yield a uniform or nonrandom weaveeffect.

To date, weave effects other than post-weaving decoration such asdyeing, screen-printing and the like, have been achieved either by weavedesign or by post-weaving treatments other than finishing. Typical ofsuch Weave designs are ribbed or corded fabrics such as piques. Bedfordcords, corduroy, or the like; crepe constructions which rely upon thetensions inherent in highly twisted yarns; and pile fabrics such asvelvet, velour, terrycloth, and friezes which employ projecting loops orsevered loops. Post-weaving fabric effects consist of selectiveshrinkage of a portion of the yarns employed in a fabric, e.g.seersucker, the thermal treatment of combination yarns having differentcoefficients of expansion or contraction, or the chemical treatment orembossing of resin treated fabrics, e.g. plisse and blister crepes.

While both of the foregoing groups of methods of achieving decorativeeffects are operable, each type is hampered by certain impediments.Unconventional weaving operations used to produce unique Weave effectssuch as Jacquard figures require modified or special looms and increaseweaving costs. Additional expense, limited utility of equipment, and thenecessity for the use of auxiliary materials such as resins or resinousyarns, often make post-weaving treatments prohibitive.

All of the foregoing impediments are multiplied in the case of fibrousglass fabrics. In the case of novelty weaves, existing looms aredesigned for the processing of yarns having conventional tension andabrasion characteristics. While the tensions of fibrous glass yarns arepartially controllable by the selection and metered application ofdifferent size compositions, the tension characteristics of sizedfibrous glass yarns vary considerably from the correspondingcharacteristics of natural and other synthetic yarns. In addition, glassfibers are mutually abrasive; prolonged contact of the moving yarn withguide eyes and contact points tends to yield quantities of fuzz or flywith attendant decreases in the strengths of the yarn. Consequently,fibrous glass yarns are not immediately adaptable to conventionalweaving techniques, let alone to more complex weaving operations.

The unique tension characteristics and tendency to pro- 3,720,571Patented Mar. 13, 1973 duce fuzz in weaving operations are results ofthe combined stiffness and resiliency of glass fibers and fibrous glassyarns. For example, fibrous glass yarns have a stiffness of 322 gramsper denier, as compared with values of 4 grams per denier for wool, 11for rayon, 6 for acetate, 18 for nylon, l0 for acrylic and 21 forpolyester yarns. This unusual stiffness is accompanied by an elasticrecovery of As a consequence of such properties in fabrics woven fromglass yarns, the yarns are highly stressed by the displacement of theindividual glass filaments and the yarn itself by the weave pattern.Such stresses are evidenced by the ease with which a fibrous glassfabric may be unraveled. To relieve these stresses, fibrous glassfabrics are subjected to a weave setting treatment in which the fabricis heated to a temperature just in excess of the softening point of theglass fibers. Upon cooling, the yarns are permanently set in the patternof the weave and consequently relieved of Weave induced stresses.

Again because of the stiffness of fibrous glass yarns, they have acritical radius of curvature, correlated to the actual diameter of thefibers, which may not be exceeded without breaking the fibers. Such alimitation prohibits the use of Weave designs which entail the bendingof the yarns through small radii. In addition, fabric affects achievedby the use of combinations or blends of glass fibers with other fibersor the use of fabric coating materials may dilute the desirableproperties of strength, translucency, ease of cleaning, wrinklerecoverability, and dimensional stability which fibrous glass fabricsnaturally possess. As a result of those properties which are unique tobrous glass fabrics, and the increased costs of the use of cornplexweaving or post-weaving treatments, the use of fabrics in fibrous glassfabrics has been substantially restricted.

An object of the present invention is the provision of methods forimparting weave effects and fabric design to a fibrous glass fabric.

Another object is the provision of methods for imparting Weave effectsand fabric design to fibrous glass fabrics without using complex weavingoperations, or special additional yarns, fibers or coatings to cause theeffects.

A further object is the provision of fibrous glass fabrics possessing aweave effect and fabric design.

Other objects and advantages of the invention will be apparent from thefollowing description.

Specifically, it has been found that the stresses inherent in a fibrousglass fabric may be employed to impart a new compacted state ofequilibrium which results in a fabric design different from the originalweave pattern, and capable of being permanently preserved in its new ormodified form.

The process entails the random application of controlled force to thefabric, in which the force applied is in itself less than that requiredto physically shift the yarns within the weave pattern. Instead, theforces applied act both to relieve in some places the stresses inducedin the yarns by the Weave pattern, and to reinforce in other placesthose stresses thereby permitting and achieving, respectively, shiftingof the yarns within the weave pattern to yield a new non-random patternwhich is determined by the stresses inherent in the yarns in theoriginal weave pattern. That is, the stiffness and resiliency of thefibrous glass yarns resist the displacement of the yarns in the weavepattern, and these forces, latent in the yarns as stressed in the weavepattern, may be rendered operative by relief or reinforcement to yield acompacted Weave effect and pseudo-embossed fabric design. The means ofrendering these forces operative is the application of outside forceswhich are capable of overcoming, neutralizing, or reinforcing the forcesalready present in the yarns in a weave pattern, but said outside forcesbeing inadequate by themselves to shift the yarns physically within theweave pattern. However, the sum of the forces induced in the yarns bythe weave pattern and the outside forces placed on the yarns by thismethod is sufficient to shift yarns within the limits of weave pattern.As a consequence of the release, neutralization, and reinforcement ofsuch forces and the shifting of the yarns, said yarns seek the path ofleast resistance to assume a new configuration. The non-random characterof the new weave pattern is the result of the fact that the originalweave pattern produced non-random or patterned stresses in the yarns,and the refiexing actions of the yarns upon the release of thoserestrictive forces also act in a non-random fashion. In the case ofglass fabrics, this new effect may then be permanently retained by meansof subjecting the fabric to a temperature in excess of the softeningpoint of the glass fibers.

In the accompanying figures, forming a part of this specification,

FIG. 1 is a top view of a fibrous glass fabric having thepseudo-embossed fabric effect, and viewed perpendicular to the plane ofthe original fabric weave,

FIG. 2 is a greatly enlarged top view of a fibrous glass fabric beforebeing treated in accordance with the present invention, again viewedperpendicular to the plane of the fabric weave,

FIG. 3 is a greatly enlarged top view of the same fibrous glass fabricillustrated in FIG. 2, but after the fabric was treated in accordancewith the present invention, and again viewed perpendicular to the planeof the original fabric weave,

FIG. 4 is a greatly enlarged top view of a single yarn from the fabricof FIG. 2, viewed perpendicular to the plane of the fabric weave,

FIG. 5 is a greatly enlarged top view of a single yarn from the fabricof FIG. 3, viewed perpendicular to the plane of the original fabricweave,

FIG. 6 is a greatly enlarged side view of a single yarn from the fabricof FIG. 2, viewed in the plane of the fabric weave-ie. rotated 90 fromthe view in FIG. 4; and,

FIG. 7 is a greatly enlarged side view of a single yarn from the fabricof FIG. 3, viewed in the plane of the fabric weave-Le. rotated 90 fromthe view in FIG. 5.

The total fabric effect is shown in FIG. 1. The zones of differingrefiectivity 11 and 12 are obvious, and the angles 13 made by thosezones with the original warp and weft directions are also shown.

FIG. 2, a greatly enlarged view of a fabric, shows in detail therelationship of the yarns before the fabric is treated in accordancewith the present invention. The uniformly equal areas of exposed yarn 14are obvious here, and may be compared with the unequal areas 17 shown inFIG. 3. FIG. 3, an equally enlarged view of a fabric, shows in detailthe relationship of the yarns after treatment in accordance with thepresent invention. This figure shows the zones of reflectivity 15 and 16which are made up of larger exposed yarn areas 17 which are in turncaused by the local compaction 18 of the yarns in one direction. Thisfigure also clearly show that both warp and weft yarns are similarlydisplaced in their equilibrium configurations.

FIG. 4 shows an individual two-strand yarn from the unprocessed fabric.This top view shows the highlighted areas 19 and 20 corresponding to thevalleys and peaks, 19 and 20 in FIG. 6, in the sinusoidal displacementof the yarns in the original fabric weave.

FIG. 5 shows a corresponding yarn taken from a sample of the same fabricafter having been treated in accordance with the present invention. Thehighlighted areas 21 and 22 corresponding to the sinusoidal valleys andpeaks, 21 and 22 in FIG. 7, caused by the original fabric weave areshown, but, in addition, the yarn is distorted with various sinuousvalleys 23 and peaks 24 in the plane of the fabric weave and in otherplanes, as schematically shown by line 25. The major displacement hereis in the plane of the fabric weave, lbut there is verticaldisplacement, shown in FIG. 7, which give the fabric a slight loft.

FIG. 6 shows a side view, within the plane of the fabric weave, of thesingle yarn shown in FIG. 4. Here the uniform, sinusoidal valleys 19 andpeaks 20 are readily seen.

FIG. 7 shows a side View, within the fabric weave, of the single yarnshown in FIG. 5. The sinusoidal valleys 21' and peaks 22' correspondingto the highlighted areas 21 and 22 of FIG. 5 are obvious, but othersinuous displacements 26, as schematically shown by line 27, are alsovisible, some of which correspond to the displacements 23 and 24 of FIG.5.

As an example of this effect, one may shift the weave of a fabric withfingernails or the point of a pencil. However, it is difficult toachieve a non-random or uniform effect by this means. Also, any effectwhich is derived is dispelled by the application of tension in the warpand fill directions. However, this illustration does show that a seriesof such shifts could rearrange the original weave pattern into a newfabric design.

It has been found desirable and expedient to apply a series of forces toa fabric with none of the individual, applied forces equaling the forcerequired to shift the yarns within the weave pattern. The repeatedapplication of such moderate forces randomly throughout the fabrlcallows the yarns to shift about locally within the limits of the weavepattern and compacts the weave pattern until a new equilibriumconfiguration is reached. Hence the random application of force is notdetrimental when continued until every portion of the fabric has beenexposed to such forces, and each yarn has reached the new equilibriumconguration. As the forces are randomly applied and stresses relieved ina given yarn, that yarn and adjacent yarns shift. Naturally, a givenpoint upon a certain yarn may experience a number of shifts since theshifting of adjacent yarns will permit subsequent shifting of that pointupon the yarn. In this fashion, the refiexive shifting of yarnsthroughout the entire fabric permits the realization of new and uniformequilibrium configurations of the weave pattern despite the non-uniformapplication of forces.

It should be noted that each weave design creates a distinct series ofstresses which accordingly yield a distinct, uniform effect upontreatment in accordance with the present invention. It is alsosignificant that the stresses existing in a given weave design, and theeffect which may be realized by means of the present invention, may bemodified or altered through the degree of twist imparted to the yarn orthe use of plied yarns in the weaving of the fabric. For example, yarnsin a fabric possess certain stresses as a result of their displacementby the weave pattern. However, additional stresses may be designed intothe fabric by changing the amount of twist of the yarns or by plying theyarns before weaving. Then the counter-action of such stresses andforces applied by means of the present invention allows the reflectiveshifting of the yarns in even another mode. While the pattern of theeffect differs for each type of weave, and its extent may be changed bycorresponding changes in weaving tensions, yarn twist, or plied yarns,for example, it should be noted that for a given weave, the effectachieved is always reproducible.

It is significant that the effect is not locally isolated at randompositions throughout the fabric, but it is a uniform result of shifts ofall of the yarns within the weave pattern. For example, in a plaintaffeta weave, the effect, since it is three dimensional, is mostobviously seen in the sheen or reflectivity of the fabric. The sheen offibrous glass fabric in a plain taffeta weave, before treatment inaccordance with this invention, is quite uniform, since this fabric isessentially flat. In contrast, the same fabric when treated exhibitsalternating zones of high and low reflectivity or sheen in the form ofelongate strips which intersect the warp and fill directions at an angleof approximately 45 degrees. These zones of different degrees of sheenor reflectivity give the fabric a pseudoembossed effect.

From the description of the invention and FIGS. and 7 depicting thechanges in individual yarns, it should be obvious that fabrics treatedin accordance with the present invention undergo a reduction in theirtwo major dimensions. The term shrinkage has not been employed due tothe fact that glass yarns do not shrink in the ordinary sense of theword-that is, the individual fibrous glass yarns do not compactthroughout their mass. The reduction is net length of the individualyarns is a result of the yarns assumption of a sinuous position in thenew equilibrium configuration of the fabric. The sinuous position of theyarns also gives the fabric a slight loft, enhancing the pseudo-embossedeffect.

While the process for achieving the described fabric effects may bedefined as the repeated random application of forces adequate tocounteract and relieve stresses inherent in the yarns in a weave patternand thereby permit the yarns to reflexively shift to relieve stresses,but such forces inadequate to directly shift the yarns, there arevarious means of accomplishing this effect.

EXAMPLE I For example, an adequate force may be applied to a fibrousglass plain weave fabric by subjecting the fabric, prior to weavesetting, to a cotton cycle of approximately twenty minutes in aconventional household washing machine. The fabric treated in thismanner contains a fabric design made by the yarns shifted in the weavepattern so that the new effect is uniformly achieved throughout theentire length and breadth of the fabric. The described effect is noteasily removed by the application of tension in the warp, fill or biasdirections or by distortion such as crumpling the fabric. In addition,the effect may be permanently set by heating the fabric to temperaturejust in excess of the softening point of the glass fibers. This can beaccomplished by either a continuous or a batch process. Upon cooling,the yarns and fibers in the new configuration are essentially free ofstresses and the new equilibrium weave effect is permanently set in thefabric. The fabric may then be finished, dyed, or printed in theconventional manner.

It should be noted that While moisture and moderate temperatures(10D-180 F.) such as those experienced in a washing machine cycle,appear to facilitate the achievement of the fabric effect, neither isessential. Moisture or moderate temperatures may assist by softening anyadhesion between the yarns at their crossover points which may resultfrom the size composition which is usually applied to glass fibers justafter their formation.

Also, the moisture may act as a lubricant to facilitate the slipping ofthe yarns one among the other within the bounds of the weave pattern.Note that in addition to the water or other liquid medium, a lubricantmay be added specifically for the above purpose. With water, any soapysubstance will work as a lubricant. With other media, other compatiblelubricants must be chosen.

EXAMPLE II The presence of moisture, lubricants, or heat is notnecessary as evidenced by the fact that the same effect may be partiallyachieved by the action of a conventional textile swing frame. The actionof the swing frame is strictly mechanical. The presence of liquidlubricants alone does not accelerate the achievement of the effect inthe absence of correspondingly accelerated applied force. This was againdemonstrated by placing a fibrous glass fabric in a rope soaper whichrepetitively immersed and withdrew the fabric from a hot water bath. Thedesired fabric effect was realized only after prolonged treatment inthat maner. Note particularly that the agitation and turbulence providedby a rope soaper is mild compared to that provided by a householdwashing machine. It is the repeated random application of moderateforces to the loosely suspended fabric which achieves the desired effectin any of these methods.

EXAMPLE III The effect is also achieved by loosely suspending the fabricand subjecting it to a jet of liquid or gas. A series of such jets isarranged in any desired pattern, so that a corresponding pattern of thepseudo-embossed effect is processed into the fabric. With this systemthe pressure used in the fiuid jets and the time of treatment varies theextent of the achieved effect.

EXAMPLE IV Another method of processing fibrous glass fabrics with adefinite pattern of the pseudo-embossed effect is to use a stencil-likedie which allows treatment of the desired areas, and essentiallyimmobilizes the areas of the fabric which are not to be treated. Such asystem can then be used with a turbulent bath of liquid, or withpressurized fluid streams as disclosed in Example III.

EXAMPLE V Still another method of processing fibrous glass fabric with adefinite pattern of the pseudo-embossed effect comprises a two-stepprocess. First, the fabric is printed with a pattern of a waterresistant film forming substance which essentially immobilizes thefabric in the printed areas. Note that the pattern of printed areas isthe negative of the desired pseudo-embossed pattern areas. Then, thisprinted fabric is treated by the repeated application of forces randomlythroughout the fabric as achieved by any of the methods disclosed in theprevious examples. Depending upon the medium and other conditions usedfor the pseudo-embossing process, a film forming substance which is morethan just water resistant may be used. In any case, the film canafterward be removed during the heat setting process, and the fabric maythen be finished, dyed, or printed in the conventional manner.

Note that the effects achieved by the methods of EX- amples III, IV, andV will not correspond precisely to the pattern of the fluid jetsstencil-like die, or printed pattern. This is due to the stresses in theyarns in the Weave patterns, particularly the tension which remains inthe unprocessed sections of the fabric. Because of those forces acomplete pseudo-embossing in those localized areas is not possible,`although it is feasible enough to give a definite effect.

EXAMPLE VI Examples I, III, IV, and V describe methods for irnpartingthe present fabric effect which are essentially isolated or batchprocesses. However, each of these methods can be modified so that theprocess is adapted to the continuous processing of the fibrous glassfabric. In such a system the fabric is advanced into a treating zonewherein the section of fabric undergoing treatment is suspended in afluid, and forces are randomly applied throughout the fabric while it issuspended to allow shifting of those portions of the fabric yarns beingtreated. Said yarns are thereby stress-relieved, and the fabric isadvanced from the treating zone having the desired pseudo-embossedfabric effect. With this continuous process, the fabric can becontinuously advanced through a heat treatment zone, emerging from thattreatment with the pseudo-embossed effect permanently set into thefabric.

This continuous system consists of a set of rollers which meters thespeed of the incoming fabric, followed by a length of slack fabric. Thisslack area is followed by the actual treating zone in which the fabricis loosely suspended in a fiuid which applies the appropriate forces tothe fabric to bring about the pseudo-embossed fabric effect. The actualtreating zone can consist of any one or combination of the systemsalready shown in previous examples. This may be a large bath of liquidwhich is violently agitated by a series of reciprocating paddles. In anyliquid bath system, the fabric must be essentially horizontal, or slowlycascading downward, to relieve internal stress insofar as possible. Analternate system is a series of fluid jets which impart a denite patterninto the fabric. Note that liquid jets may also be employed to increaseagitation in the liquid bath system. Or, alternatively, a stencil-likedie can be used with either fiuid streams or a liquid bath. Likewise,the fibrous glass fabric printed with a pattern of a water resistantfilm forming substance may be continuously processed in the slack washersystem or with uid jets. In any of these treating systems, the extent ofthe fabric effect may be controlled by metering the treatment time byclose control of the speed with which the fabric passes through thetreating zone and the number of applications of force. The length of thetreating zone can be designed so that an appropriate amount of fabricundergoes treatment for the desired length of time. After emerging fromthe treatment zone, another leader section of slack fabric is maintainedbefore the fabric proceeds to heat treatment or other processing.

Regardless of the specific method. used, the extent or degree of thefabric effect which may be achieved is limited for a particular fabricstructure or original weave pattern. The effect is achievedprogressively during the time of treatment, but the fabric eventuallyreaches a stage at which additional treatment evokes no further changein the fabric, For example, a plain taffeta weave fabric achieves adegree of effect after a twenty minute Wash cycle in a household washingmachine which is not increased or changed by additional treatment.However, if one removes samples of the fabric from the process at twominute intervals during the treatment, the progressive achievement ofthe fabric effect may be observed. This illustrates that the relief ofstresses and compacting of the yarns into a final equilibriumconfiguration is a progressive process which is achieved only after theyarn stresses have been substantially relieved by this mechanicalprocess. The progresive achievement of the fabric effect is notnecessarily uniform, but the final equilibrium configuration gives anessentially uniform effect.

Although the present invention has been discussed as used on fibrousglass fabrics woven from yarns made of glass fiber coated only with theusual sizing compounds, it may 'be performed on fabrics woven with yarnscoated with any substance which does not destroy the inherent stiffnessand resiliency of the fibrous glass yarns, and which provides a coatingwhich is slick enough to allow the yarn to shift easily within thelimits of the Weave pattern. For example, fibrous glass yarns coatedwith polyethylene, polypropylene, or polyvinyl chloride could be used infabrics suitable for treatment in accordance with the present invention.Combination yarns of brous glass strand plied with organic strand mayalso be used. Such combinations of viscous and glass yarns have beenused. The same combination of glass and organic strands may be used incore yarns with the glass strand as either the core or the wrapper, andfabrics made with such yarns are suitable for treatment in accordancewith the present invention. Indeed fabrics woven from yarns containingno glass whatsoever could lend themselves to the present invention ifthe properties of the yarns were such that stresses are produced in theyarns by the weave pattern, and the yarns are slick enough and thestresses large enough to allow the yarns to shift within the weavepattern to relieve the stresses in the yarns when treated in accordancewith the present invention. Also, fabrics woven with blends of differenttypes of combination and coated yarns can be processed by the method ofthe present invention.

Various modifications of the above described invention will be apparentto those skilled in the art, and such modifications can be made withoutdeparting from the spirit and scope of the present invention.

We claim:

1. An embossed fibrous glass fabric comprising warp and weft yarns, saidyarns having been originally in a stressed condition due to theirdisplacement from an essentially straight configuration into sinusoidalpaths in the original fabric weave pattern, said yarns now lying inlaterally and vertically shifted, stress-relieved, and compactedequilibrium configurations of the weave pattern providing a uniformpseudo-embossed fabric effect.

2. The fibrous glass fabric of claim 1 having the maximum possiblepseudo-embossed effect wherein the warp and weft yarns lie in the final,essentially stress-relieved equilibrium configuration.

3. The fibrous glass fabric of claim 1 having a lightly pseudo-embossedeffect wherein the warp and weft yarns lie in an intermediate, partiallystress-relieved equilibrium con'figuration.

4. The 'fibrous glass fabric of claim 1 wherein the uniformpseudo-embossed fabric effect is permanently heat set into the fabric.

References Cited UNITED STATES PATENTS 2,083,248 6/1937 Teres 161-732,685,120 y8/1954 Brant 161-73 WILLIAM A. POWELL, Primary Examiner U.S.'CL X.R.

